Plug locking attachment for ektension cords



Aug. 24, 1948. R. o. WILLIAMS 2,447,783

I PLUG LOCKING ATTACHMENT FOR EXTENSION CORDS Filed Dec. 28, 1944 5 Sheets-Sheet 1 In uelltor Rmnmzo O. WILLIAM5 Aug. 24, 1948. Y R. o. WILLIAMS ,447,783

PLUG LOCKING ATTACHMENT FOR EXTENSION CORDS Filed Dec. 28, 1944 3 Sheets-Sheet 2 Inventor RICHARD O.WILL|AM5 eon Wa la; 25 M Aug. 24, 1948. R. o. WILLIAMS Q 2,447,783

PLUG LOCKING ATTACHMENT FOR EXTENSION CORDS Filed Dec. 28, 1944 v 3 Sheets-Sheqt 5 RmHARDQWILUA'MS socket.

Patented Aug. 24, 1948 inwemomeme ncrmemuawrmon iEKTENSION'GORDS malaria-Wi iams, Les Auss es, .Ga1i a si no of -oneehalf itomlolph H. .Ross, Loss Angele Galif.

.a nnsann n temm as, sIBMsESMZ iBJIN .05 2

The present, invention relates to new and alien- .ful improvements ,in nluasior extension cords.

and :the invention has for .its primary iohieot t provide meansnforljocking the pluain an el ctri socket or ,fixture to plug and the cover plate of the electric socket and adapted iforimovementiintoand out of engagement with each other to secure the plug in position inthe socket.

An important object of the "present invention is. to provide .springebiased ,meansrotatably mounting the locking lugs on the 9 .1. .8 and adapted upon partial rotary movement to ,mo ve .said lugs into and out of engagement with retaining lugs carried "by'the pover plate-of the A stillfurther obfi-ectis toprovide aplug and socket connecting means for extension cords of a simple and practical construction, which is efflcient and reliable in use, relatively inexpensive to manufacture and otherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming part hereof, wherein like numerals refer to like parts throughout, and in which:

Figure 1 is a fragmentary elevational view of the cover plate of an electric socket showing the plug in position for locking engagement therewith.

Figure 2 is a similar view showing the plug in locked position.

Figure 3 is a longitudinal sectional view of the plug detached from the socket.

Figure 4 is a similar view showing the plug in locked position with the cover plate of the socket.

Figure 5 is a side elevational view of the plug with the locking lugs removed therefrom.

Figure 6 is a front elevational view thereof.

Figure 'I is a side elevational view of the locking lugs and sleeve for slldably mounting the lugs on the plug.

Figure 8 is an end elevational view with parts broken away and shown in section.

insuresi asideelevationa viewoftharetaining ut for the leeve .QfIthe l cking .luss harried hy themlus- I l yFigure 310,15 anon-t elevational viewrthereor.

F ure 11.15 a perspective .view of .the lockin lu s v(retrievedfrom the .s eevs- Figure 12 is a siderelevational .viewpf thecoil s ngpositioned-between the plu n -ithei sm elues p Fieur 1s-afrontsl. vatie a viewnfi ne 10i -:,co,ver;p1ate vfor .therel atti su k t.

:Flsure .411s .eis -milar vilewrof a m dified .torm

refrce e plate. i v, t

Figur iai e.fronte evationa vi w; howing the cover p te mposition ont hesq k t.

.zEieure rials-a s mila r e .i lustratinaa fu t m difi atio 1 2f.thes v plate- Referring now to the drawings in detail, wherein for the purpose of illustration I have disclosed a preferred embodiment of the invention, the numeral 5 designates an electric plug of insulation material and tubular form and having the pair of conductor prongs 6 secured in a recess 1 at the inner end of the plug by means of the screws 8, the prongs being adapted for connection with the circuit wires extending longitudinally through the plug.

The outer surface of the plug 5 is of a substantially stepped formation to provide a flange 9 at the inner end of the plug to form a shoulder l El and a flange I l of reduced diameter outwardly of the flange 9 to form a shoulder I2, the outer portion of the plug extending from the shoulder 12 being in the form of a reduced stem [3 which is externally threaded at its outer end, as indicated at H.

A sleeve I5 of insulation material is slidably mounted on the flanged portion ll of the plug and surrounds the stem portion l3 thereof in spaced relation therefrom.

A pair of locking lugs l6 project outwardly in opposite directions from legs I! embedded in the sleeve l5, the legs projecting beyond the inner end of the sleeve with their outer ends offset, as will be apparent from an inspection of Figures 3 and 4 of the drawings to extend along diametrically opposite sides of the flanged inner end portion 8 of the plug. The legs [1 are connected at their inner ends by a ring member l8 which is slidably mounted on the stem 13 and engaged by one end of a coil spring l9 which has its other end bearing against the shoulder l2 of the flange ll of the plug, whereby to yieldably urge the sleeve 15 and lugs l6 outwardly on the plug. A nut 20 of insulation material is threaded on the outer end of the stem l3 to limit outward movement of the sleeve .and to retain the same in position on the plug.

The prongs 6 of the plug are adapted for insertion in the usual electric socket or, outlet, such as shown at 2| in'Figures 13 and"16,the socket usuallybeing provided with a cover plate 22 retained in position by one or more screws 23. P0- sitioned over the cover plate 22 is a retaining plate 24 held in position by the screws 23, the i retaining plate being either of a rectangular. form,

as illustrated in Figures 1, 2 and 13, with a single socket opening 26 therein, or of a skeletonpolygonal form with a single socket opening 26,"as

illustrated in Figure 16, or of a rectangular form It is believed that the details of construction and manner of use of the device will be readily understood from the foregoing without further detailed explanation.

Having thus described the invention, what I claim is:

Means for locking an electric plug in an outlet socket having a retaining plate attached thereto with outwardly projecting lugs, said plug comprising a tubular body having a pair of stepped flanges and provided with end prongs for insertion in said socket, a sleeve endwise slidable in opposite directions on said bodyand rotatable thereon, a pair of legs extending part way through said sleeve longitudinally thereof upon opposite sides of the same and having right angled outer ends extending out of said sleeve forengaging behind said lugs upon rotation of the sleeve, a ring in said sleeve concealed thereby with two socket openings 26, as "illustrated in Figure 14, or of skeleton polygonal form with two socket openings 26 as illustrated. in Figure In each of the forms of the retainer plate a pair of lugs 25 are struck from the surfacethereof at diametrically opposite sides of the opening 26 formed therein for exposing the socket 2!, the lugs having a free edge disposed adjacent the opening and behindswhich the lugs I5 carried by the plug 5 are adapted for engagement by a partial rotation of the sleeve I5.

Accordingly, in the operation of the device, the prongs 6 of the plug 5 are inserted in the socket 2| and the sleeve l5 moved inwardly along the plug 5 and then partly rotated to move the lugs I6 carried by the sleeve under the lu s 25 carried by the retainer plate 24, whereby the plug will be locked in position to the retainer plate, as shown in Figure 4 of thedrawings.

The spring I9 urges the plug 5 inwardly and at the same time urges the sleeve 15 and lugs l6 outwardly to prevent accidental displacement or separation of the plug from the socket.

one direction.

and'conne'cting said pair of legs at the inner ends thereof and slidably and rotatably mounted on the body, and a coil spring concealed in said sleeve and surrounding said body between one of the-flanges thereof and said ring and urging said sleeve endwise in one direction, said sleeve being endwise slidable in the opposite direction in opposition tosaid spring to move said outer ends said sleeve to limit sliding of the sleeve in said RICHARD O. WILLIAMS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 2,240,050 Nuebling Apr. 29, 

